Creepers are used to provide support for users in a variety of applications, an important example of which is the use of creepers by mechanics to provide mobile support while working on the underside of vehicles. Creepers generally include wheels attached to the lower side of a unitary panel or assembled body. The wheels are adapted to provide multidirectional mobility to the creeper while supporting the user, and enable the user to work in environments with low vertical clearances. For a creeper to perform as intended, it must have an adequately rigid and strong construction to support the entire weight of the user. Yet, creepers that are constructed with a one-piece design are often cumbersome and awkward to store due to their size.
Several prior art creepers have been suggested that provide the necessary support to the user while and are capable of being collapsed for efficient storage. For instance, both U.S. Pat. No. 4,580,799 to Quinonez and U.S. Pat. No. 4,889,352 to Chamberlin, Jr. et al. disclose creepers formed by two hinged sections. These creepers can be folded in order to reduce their overall size when not in use. A mechanic using such a creeper must remove himself or herself from the creeper before collapsing the creeper.
Other prior art creepers have been suggested that are composed of two sections that can be separated. For instance, U.S. Pat. No. 5,022,670 to Cote et al. discloses a creeper that is constructed of two separable panels. The separability of the creeper is intended to enable the creeper to enter a confined space, particularly an attic. Notably, the panels are connected such that they are not coplanar, but are instead joined at an angle of less than 180 degrees. This aspect of the creeper is essential to allow the user to move the creeper over uneven surfaces, such as ceiling joists in an attic. The two panels are coupled by a pair of bars that are bent at an angle. The bars are secured to one panel and receivable within a pair of channels formed in the second panel. Each bar is secured to a respective channel by a locking pin that is accessible through a lower surface of the creeper. The creeper is supported by a number of small wheels located along each side of the creeper, with the wheels being adapted to permit mobility in only the longitudinal direction of the creeper.
The creeper to Cote et al. is designed to address the difficulties of working on uneven surfaces. Although composed of separable panels, the creeper does not allow the panels to be easily separated while in use, since the locking pins are located on the lower surface of the creeper inboard of the wheels. The separability of this creeper is further complicated by its wheels, which necessarily have small diameters and are closely spaced to facilitate mobility over uneven surfaces. The small diameter wheels reduce the clearance beneath the creeper, making it essentially impossible to gain access to the locking pins while the user is seated on the creeper.
Another separable creeper is shown in U.S. Pat. No. 5,297,809 to Chen. The purpose of Chen's separable creeper is to allow easy portability, packing and shipment. According to Chen, two panels are joined by use of a dovetail mortise and holes attached perpendicularly to a first of the panels, and a dovetail tenon and posts attached perpendicularly to the second panel. The panels are attached by engaging the dovetail tenon into the dovetail mortise and the posts into the corresponding holes extending through the second panel. Consequently, the method by which the panels are connected and separated is rather difficult. Furthermore, the design requires a manufacturing process by which each post and its corresponding hole are fabricated within relatively close tolerances, such that the fit between each post-hole combination contributes stiffness to the creeper and thereby provides adequate support the weight of the user. Similarly, the dovetail mortise and the dovetail tenon must also be close-fitting. Notably, assembly and disassembly of this creeper require the panels to be separated by moving one of the panels in a perpendicular direction relative to the plane of the creeper. Therefore, if the user desires to disassemble the creeper while remaining seated, the panel with the posts must be raised perpendicular to the creeper with sufficient force to disengage the posts with their holes and the disengage the dovetail tenons with their dovetail mortices, a rather difficult operation to perform while seated. Accordingly, Chen's creeper cannot be easily assembled and disassembled while supporting the user.
From the above, it can be seen that it would be desirable to have a creeper composed of separable portions that can be readily disassembled, even if the user remains seated on one of the portions. It would be further desirable if such a creeper was more versatile than prior art creepers, so as to enable use of the creeper under a wider variety of circumstances.